Rawtherapee - How do I enable the film negative tool please?

hello again. I was away travelling for a couple weeks. You get good result.
I try now to get some sense of the technicalities on your main thread here

but I guess i will just have to wait for some code to appear in the current official git. By now nothing when I build the recent source.
I kept testing with different kind of emulsions (Ektar, Protra 160, Portra 400, Lomography 100, Lomography 400) and diverse kind of daylight and lightning. The only practical one-click inversion that I have been using until now with Gimp does fail with quite some negatives, requiring a lot of manual adhoc post-processing, while NegativeLabPro works very well consistently (have tried 12-shots demos on a couple diffferent virtualboxes …) so considering to buy.
I can post more raw negs for you to play, if that’s of some use, but also I should see what is said on Gimp boards or some place where color negative inversion in general may be discussed.
In some cases the positive produced by Vuescan or EpsonScan from the Epson V700 is still the best image, yet NLP outperforms it and basically it seems because in the default setting it uses Fuji Frontier scanner colours matrix, as I understand.
I need also to shot some 35mm and play with the Proscan 10T that I use for these.